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linux-kernelsizeobjdumpreadelf

"size" vs "readelf -t" command gives different segment length

size my_obj.o, lists the size of text, .data segments in bytes.

but readelf -t my_obj.o gives different size (much lesser) of text & data segments.

 **text    .data   .bss**
 200890   4797     88   
 146172   1960     88

object dump also gives similar results.

Solution

  • size by default runs in "Berkeley compatibility mode". In this mode, it will include certain non-executable read-only sections that have the ALLOC bit set, such as .rodata, as text, and it will classify some non-executable non-NOBITS sections as data instead of bss. If you run size in "System V compatibility mode", size -A my_obj.o, it should give you sizes close to the values reported by readelf -t.